DMs to unreachable peers use store-and-forward instead of failing instantly (#1415)

* DMs to unreachable peers route through store-and-forward; drop stale reachability gates

Field-found: sendPrivateMessage pre-judged reachability and marked the
message failed without ever calling the router, so the retained outbox,
courier deposits, and bridge drops never ran — a DM composed after a
peer's reachability window lapsed was dead on arrival while an identical
one sent a minute earlier delivered. Messages now always route; a live
path earns "sent", everything else stays "sending" until the router
reports carried/delivered or expires it as failed.

A sweep for sibling gates found and fixed:
- startPrivateChat refused offline non-mutual favorites ("mutual favorite
  required for offline messaging") — store-and-forward only needs the
  recipient's noise key, so the gate and its string are gone.
- markPrivateMessagesAsRead skipped the whole receipt pass for peers
  without a stored Nostr key, starving mesh-connected non-favorites; the
  router picks the transport now (sentReadReceipts dedups the parallel
  PrivateChatManager path).
- DM/geoDM blocked notices and the unknown-group error posted to the
  active public timeline; they now land in the thread they're about via
  addLocalPrivateSystemMessage.
- Banned copy: literal "user" fallbacks in code become "anon" (the
  default-nickname convention), and es/fr/it/pt translations of four keys
  still saying usuario/utilisateur/utente/usuário now say person. Orphaned
  keys removed (system.dm.unreachable, content.delivery.reason.unreachable,
  system.chat.requires_favorite).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* Deflake BLEServiceCoreTests: longTimeout for positive waits

CI flaked on duplicatePacket_isDeduped: the first message landed after the
5s wait expired on a loaded runner (the test's later count==1 assertions
passed, proving late delivery, not lost delivery). All four positive waits
in the file now use TestConstants.longTimeout, which exists for exactly
this — waitUntil returns as soon as the condition holds, so passing runs
never pay the longer ceiling.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* Fix read-receipt test contamination; baseline Periphery noiseKey flake

Two CI failures, both environmental:

- markReadReceiptSent_returnsFalseOnSecondCall flaked because every test
  ChatViewModel shared one per-process read-receipts scratch suite; the
  lifecycle test persists the same "read-1" ID (a path the receipt-gate
  removal now reaches), and test order decided who saw whose state. Each
  instance now gets its own UUID-suffixed suite.

- Periphery intermittently misses the loadFromDisk read of
  PrekeyBundleStore.StoredBundle.noiseKey and fails --strict with a false
  "assign-only" finding (recurrence of a known flake). Its USR is
  baselined; an in-source periphery:ignore can't work because strict mode
  flags it as superfluous on runs where the indexer gets it right.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

---------

Co-authored-by: jack <jackjackbits@users.noreply.github.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

bitchatTests/ChatViewModelExtensionsTests.swift

@@ -71,8 +71,11 @@ struct ChatViewModelPrivateChatExtensionTests {
         // Check MockTransport implementation... it might need update or verification
     }
 
+    /// An unreachable recipient no longer means instant failure: the message
+    /// is routed anyway so the router's outbox/courier/bridge machinery can
+    /// deliver it, and it stays "sending" until a router callback resolves it.
     @Test @MainActor
-    func sendPrivateMessage_unreachable_setsFailedStatus() async {
+    func sendPrivateMessage_unreachable_staysSendingForStoreAndForward() async {
         let (viewModel, _) = makeTestableViewModel()
         let validHex = "0102030405060708090a0b0c0d0e0f100102030405060708090a0b0c0d0e0f10"
         let peerID = PeerID(str: validHex)
@@ -80,11 +83,7 @@ struct ChatViewModelPrivateChatExtensionTests {
         viewModel.sendPrivateMessage("Hello", to: peerID)
 
         #expect(viewModel.privateChats[peerID]?.count == 1)
-        let status = viewModel.privateChats[peerID]?.last?.deliveryStatus
-        #expect({
-            if case .failed = status { return true }
-            return false
-        }())
+        #expect(viewModel.privateChats[peerID]?.last?.deliveryStatus == .sending)
     }
     
     @Test @MainActor
@@ -780,8 +779,10 @@ struct ChatViewModelGeoDMTests {
         #expect(isFailed(status: viewModel.privateChats[convKey]?.last?.deliveryStatus))
     }
 
+    /// The blocked notice belongs in the DM thread the person is typing in,
+    /// not on the active location-channel timeline.
     @Test @MainActor
-    func sendGeohashDM_blockedRecipient_marksFailedAndAddsSystemMessage() async {
+    func sendGeohashDM_blockedRecipient_marksFailedAndAddsSystemMessageInThread() async {
         let (viewModel, _) = makeTestableViewModel()
         let geohash = "u4pruydq"
         let recipientHex = "0000000000000000000000000000000000000000000000000000000000000003"
@@ -793,9 +794,11 @@ struct ChatViewModelGeoDMTests {
 
         viewModel.sendGeohashDM("hello", to: convKey)
 
-        #expect(viewModel.privateChats[convKey]?.count == 1)
-        #expect(isFailed(status: viewModel.privateChats[convKey]?.last?.deliveryStatus))
-        #expect(viewModel.messages.contains(where: { $0.sender == "system" }))
+        let thread = viewModel.privateChats[convKey] ?? []
+        #expect(thread.count == 2)
+        #expect(isFailed(status: thread.first?.deliveryStatus))
+        #expect(thread.last?.sender == "system")
+        #expect(!viewModel.messages.contains(where: { $0.sender == "system" }))
     }
 
     @Test @MainActor